The present invention relates to a compressor and, more particularly, to a compressor for compressing refrigerant, suitable for use in air conditioner for vehicles.
Vane type rotary compressors have been rated high, because of high driving and compression efficiencies. Particularly, the vane type rotary compressor having vanes disposed in the stationary housing attracts attention, because of advantages of high driving efficiency and reduced cost of production which are derived from the simplification of construction of rotary parts.
This type of compressor, however, involves various problems. Namely, in existing compressors of the kind described, the suction and delivery ports, through which a working chamber defined by the housing, rotor and the vanes communicate with suction and delivery side, are formed stationarily in the housing. Therefore, a temperature gradient is inevitably generated locally in the housing, due to the difference between the refrigerant temperature at the suction side and that at the delivery side, possibly resulting in the thermal distortion of the housing. This arrangement also leads to a poor efficiency of cooling of the rotor, resulting in a temperature rise only in the rotor. In addition, since the parts of the housing in sliding contact with the rotor, vanes and bearings are lubricated by the lubricant forcibly supplied by an oil pump incorporated in the compressor, the cost of the compressor has been rendered high, due to the installation of the oil pump and accessories.
It is therefore an object of the invention to provide a compressor which is free from the distortion attributable to the difference in temperature of the fluid between the suction and delivery sides of the compressor.
It is another object of the invention to provide a compressor which can increase the efficiency of sucking of the fluid to be handled into the working chamber defined in the housing.
It is still another object of the invention to provide a compressor in which the flow of the fluid in the working chamber is suitably utilized such that the oil content in the fluid is supplied to the portions which require lubrication, e.g. the end surface of the rotor, bearings and shaft seal of the driving shaft of the rotor.
It is a further object of the invention to provide a compressor in which the reversing of the fluid compressed in the working chamber of the housing back to the suction chamber is prevented to improve the volume efficiency of the compressor. It is a still further object of the invention to provide a compressor in which the supply of the lubrication oil to the end surface of the rotor is made without fail, so as to improve the working efficiency and the durability of the compressor.
It is a still further object of the invention to provide a compressor in which the rate of lubrication oil supply to the longer-diameter part of the rotor, which is rotated at a higher peripheral or tangential speed, is increased as compared with the other portions, so that the wear at these longer-diameter portions may be reduced.
It is a still further object of the invention to provide a compressor in which the pressure at which the vanes contact the rotor is optimized to increase the compression efficiency and durability of the compressor, and to reduce the mechanical impact or shock at the starting of the rotor.
It is a still further object of the invention to provide a compressor in which the compression work is commenced without fail, at the time of starting of the rotation of the rotor.
It is a still further object of the invention to provide a compressor in which the amount of oil staying in the rotor during running is adjusted optimumly.
These and other objects of the invention will become clear from the following description of the preferred embodiment taken in conjunction with the accompanying drawings, as well as from the appended claims. Various advantages derived from the invention which are not mentioned in the specification with be obvious to those skilled in the art.